Fibers for electric flocking and electrically flocked article

ABSTRACT

A poly(trimethylene terephthalate) short fiber having a cut length of 0.2-3 mm, and electrostatically flocked goods prepared by electrostatically flocking the poly(trimethylene terephthalate) fiber, are described. 
     According to the present invention, there can be provided a fiber, for electrostatic flocking, which has excellent tread-proofness, scratch resistance and light resistance, and electrostatically flocked goods which have an excellent appearance.

TECHNICAL FIELD

The present invention relates to fibers for electrostatic flocking, andelectrostatically flocked goods. More particularly, it relates topoly(trimethylene terephthalate)-based fibers, for electrostaticflocking, which have an excellent dispersibility, and electrostaticallyflocked goods which have an excellent appearance and also have anexcellent tread-proofness and light resistance.

BACKGROUND ART

As the fiber for electrostatic flocking, a nylon fiber has exclusivelybeen employed heretofore. In particular, the nylon fiber having softhand has exclusively been employed in uses such as automobile interiors,but has poor light resistance. Thus, there has been requiredelectrostatically flocked goods which have soft hand, dispersibility ofstanding fibers, and an excellent appearance in uses such as car seatcoverings.

On the other hand, a general-purpose polyester fiber containingpolyethylene terephthalate) as a principal component has an excellentlight resistance as a fiber for electrostatic flocking. However, ageneral-purpose polyester fiber has a poor tread-proofness, a soft hand,poor dispersibility of standing fibers and a poor appearance so that itsuse is limited. There has been disclosed a suggestion (Unexamined PatentPublication (Kokai) No. 5-59610) of improving poor tread-proofness byusing a fiber having a flat section in electrostatic flocking of thegeneral-purpose polyester fiber. As a result, the properties wereslightly improved, but satisfactory properties have not been obtained.Therefore, a further improvement has been required.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a fiber forelectrostatic flocking, which has an excellent dispersibility, andelectrostatically flocked goods which have an excellent appearance andalso have excellent tread-proofness, scratch resistance and lightresistance.

The present inventors have found that the object can be attained byselectively employing a specific polyester fiber as a fiber forelectrostatic flocking.

That is, the object of the present invention can be attained by apoly(trimethylene terephthalate)-based fiber for electrostatic flocking,the fiber being a short fiber having a cut length of 0.2-3.0 mm.

The present invention is also directed to electrostatically flockedgoods formed of the poly(trimethylene terephthalate)-based short orchopped fiber having a cut (chopped) length of 0.2-3.0 mm.

The present invention will be described in detail below.

The poly(trimethylene terephthalate)-based fiber used in the presentinvention refers to a polyester fiber comprising trimethyleneterephthalate units, as principal repeating units, in an amount of about50 mol % or more, preferably 70% or more, more preferably 80 mol % ormore, and most preferably 90% or more. Accordingly, thepoly(trimethylene terephthalate)-based fiber according to the presentinvention includes a poly(trimethylene terephthalate) fiber containinganother acid component and/or glycol component, as a third component, inthe total amount of about 50 mol % or less, preferably 30 mol % or less,more preferably 20 mol % or less, and most preferably 10% or less.

Poly(trimethylene terephthalate) is synthesized by combiningterephthalic acid or a functional derivative thereof, for example,dimethyl terephthalate, with trimethylene glycol in the presence of acatalyst under suitable reaction conditions. In this synthesis process,a suitable one or more third components may be added to form a copolymerpolyester. Alternatively, polyester other than poly(trimethyleneterephthalate), for example, poly(ethylene terephthalate), nylon andpoly(trimethylene terephthalate) may be blended or conjugate-spun(sheath core, side-by-side, etc.) after they were separatelysynthesized.

The third component to be added includes, for example, an aliphaticdicarboxylic acid (e.g. oxalic acid, adipic acid, etc.), an alicyclicdicarboxylic acid (e.g. cyclohexanedicarboxylic acid, etc.), an aromaticdicarboxylic acid (e.g. isophthalic acid, sodium sulfoisophthalic acid,etc.), an aliphatic glycol (e.g. ethylene glycol, 1,2-propylene glycol,tetramethylene glycol, etc.), an alicyclic glycol (e.g.cyclohexanedimethanol, etc.), an aliphatic glycol containing aromatic(e.g. 1,4-bis(β-hydroxyethoxy)benzene, etc.), an polyether glycol (e.g.polyethylene glycol, polypropylene glycol, etc.), an aliphaticoxycarboxylic acid (e.g. ω-oxycaproic acid, etc.) and an aromaticoxycarboxylic acid (e.g. P-oxybenzoic acid, etc.). A compound having oneor three or more ester forming functional group(s) (e.g. benzoic acid,glycerin, etc.) can also be used as long as the polymer is substantiallylinear.

Furthermore, matting agents such as titanium dioxide, stabilizers suchas phosphoric acid, ultraviolet absorbers such as a hydroxybenzophenonederivative, nucleating agents for crystallization such as talc,lubricants such as aerogyl, antioxidants such as hindered phenolderivative, flame retardants, antistatic agents, pigments, fluorescentwhiteners, infrared absorbers and defoamers may be contained as thecomponent to be added.

In the present invention, the poly(trimethylene terephthalate)-basedfiber can be prepared by applying any known spinning method to theabove-mentioned poly(trimethylene terephthalate) polymer. For example,any of a method of preparing an unstretched yarn (undrawn) at a take-uprate of about 1500 m/min and stretching/twisting the resulting yarns byabout 2-3.5 times (conventional spinning process), a direct stretchingmethod wherein a spinning step and a stretching or drawing twisting stepare directly connected (spin-draw process) and a high-speed spinningmethod whose take-up rate is 5000 m/min or more (spin take-up process)can be employed.

The poly(trimethylene terephthalate) fiber used in the present inventionpreferably has an elastic recovery at 20% extension of 70-98%, and morepreferably 87-98%, thus providing a fiber having an excellent appearanceand tread-proofness.

If the poly(trimethylene terephthalate)-based fiber having theabove-mentioned elastic recovery is prepared, the spinning temperatureon melt spinning of the polymer is preferably controlled within a rangeof 270-290° C., and more preferably 270-280° C. As the spinning method,for example, a spin draw method and a conventional spinning processwherein the take-up rate is within a range of 1000 to 2000 m/min arepreferred. To obtain the elastic recovery of 87-98%, the spinning methodof the latter is particularly preferred. The elastic recovery of thefiber thus obtained is markedly larger than that of the nylon fiber andpoly(ethylene terephthalate) fiber used for electrostatic flocking as ismentioned in the examples and comparative examples describedhereinafter.

The poly(trimethylene terephthalate)-based fiber used in the presentinvention can have a section with polygonal shapes, polyphyllous shapes,hollow shapes and free shape, for example, circular shape, triangularshape, L-shape, T-shape, Y-shape, W-shape, octaphyllous shape, flatshape and dog-bone shape.

The fiber for electrostatic flocking of the present invention is a shortfiber having a cut length of 0.2-3 mm. When the cut length exceeds 3.0mm, the tread-proofness is lowered and the surface appearance becomespoor. On the other hand, when the cut length is smaller than 0.2 mm, thehigh-grade appearance and softness are impaired, which is not preferred.The cut length is preferably 0.5-3.0 mm, and more preferably 0.7-1.5 mm.

The fiber for electrostatic flocking of the present invention can beobtained by cutting a tow having tens to millions of denier, which isobtained by a method of stretching an unstretched yarn tow or bundlingstretched yarn to form a tow, into cut or chopped fibers having a lengthof 0.2-3.0 mm by using a guillotine cutter. A fiber having an arbitrarythickness can be selected, and the single yarn denier is preferably0.5-10 d, and more preferably 1-5 d.

The fiber for electrostatic flocking of the present invention ispreferably subjected to a pre-electrostatic flocking treatment(pre-treatment) for improving the separating and flying properties ofthe aggregated short fibers in a electrostatic flocking, for example,pre-electrostatic flocking treatment with a treating solution of asilicon compound such as sodium silicate or potassium silicate, and awater-soluble potassium compound such as potassium formate or potassiumacetate.

The fiber for electrostatic flocking of the present invention issuperior in the dispersibility of the electrostatically flocked shortfibers to a conventional coating flock. An excellent dispersibilityleads to an excellent appearance of the electrostatically flocked good.

The electrostatic flocking is carried out by generating a high-voltageelectrostatic field between electrodes facing each other, disposing afabric substrate coated with an adhesive on one electrode, applyingcharges to the pre-electrostatic flocking treated short fibers andenabling the short fibers to fly toward the fabric substrate from theopposite electrode. In this case, when plural short fibers areintegrated by fusion or pressing due to the poor dispersibility of theshort fibers, or long fibers are included without being cut into piecesof a fixed length, electrostatic flocking is not uniformly carried outand the resulting electrostatically flocked goods have a poorappearance.

There can also be used a method of preparing electrostatically flockedgoods having an excellent appearance by further comprising the step ofpassing the pre-electrostatic flocking treated short fibers through amesh to remove the integrated fibers and long fibers. However, when theabove-mentioned single fiber has a poor dispersibility, the amount ofthe short fibers passing through the mesh is reduced, thereby to lowerthe yield and to raise the production cost. Thus, an excellentdispersibility is required of the fiber for electrostatic flocking.

The electrostatically flocked goods of the present invention can beobtained by applying the fiber for electrostatic flocking of the presentinvention in a high-voltage electrostatic field to fabric substrates,for example, knits such as tricot, woven fabrics and non-woven fabrics,which are coated with an adhesive made of vinyl acetate resin, acrylateresin, acrylic or urethane-based resin or a mixture thereof; and fabricsubstrate such as various resin sheets made of resin such as vinylchloride resin.

The fiber constituting the fabric substrate such as knit used in theelectrostatically flocked goods of the present invention is notspecifically limited, and may be those of special fibers such asultrafine fiber and dividable ultrafine fiber according to the use andthe required quality. Colored electrostatically flocked goods may beobtained by any method such as coloring of raw materials and dyeing offibers or product.

BEST MODE FOR CARRYING OUT THE INVENTION

The following examples further illustrate the present invention indetail. The performances were evaluated by the following procedures.

(1) Evaluation of Dispersibility of Fibers for Electrostatic Flocking

10 g of fibers for electrostatic flocking (electrification pre-treatedfibers) are put in a cylindrical (80 mm in diameter and 100 mm inlength) mesh (mesh #20) and the mesh is rotated 25 times (60 rpm). Then,the weight (W) of fibers passed through the mesh is measured and theproportion (mesh pass %) is calculated. The larger the proportion, thebetter the dispersibility and appearance of the electrostatic flockedgood.

Mesh pass (%)=W/10×100

(2) Appearance of Electrostatically Flocked Good

The appearance of the electrostatically flocked good prepared byapplying the flock to the surface of a vinyl chloride sheet in a weightof 80-100 g/m² was visually judged whether or not the length of erectfibers of the electrostatically flocked good is uniform and the flockingdensity varies according to the following five-grade criteria.

Class 1: extremely uneven surface with a large difference in length oferect fibers and very noticeable unevenness in flocking density

Class 2: uneven surface with a large difference in length of erectfibers and noticeable unevenness in flocking density

Class 3: uneven surface with a difference in length of erect fibers

Class 4: generally even surface with a small difference in length oferect fibers

Class 5: very even and uniform surface with no difference in length oferect fibers

(3) Elastic Recovery at 20% Extension of Fiber

The fiber was attached to a tensile tester under the conditions of aninitial load of 0.01 g/d and a distance between chucks of 20 cm,stretched to an extension of 20% at a testing speed of 20 cm/min, andthen allowed to stand for one minute. The fiber was returned to theoriginal length (L) at the same speed and the residual extension (L₁)was read from a transfer distance of the chuck in a state where a stressis applied. Then, the elastic recovery at 20% extension of fiber wascalculated by the following equation.

Elastic recovery (%) at 20% extension of fibers =(L)−L₁)×100/L

(4) Evaluation of Tread-proofness of Electrostatically Flocked Good

A weight having diameter of 3 cm and weighing 200 g was placed on thesurface of standing fibers of the electrostatically flocked goodsprepared by applying the flock to the surface of a vinyl chloride sheetin a weight of 80-100 g/m² and, after being allowed to stand for 24hours, the weight was removed. Then, the electrostatically flocked goodswere allowed to stand for additional one hour and the shadow (dark area)of flattened lie of piles was visually judged according to the followingfive-grade criteria.

Class 1: flattened lie of piles is not recovered and the impressedpattern of the weight is exceedingly noticeable

Class 2: flattened lie of piles is not recovered and the impressedpattern of the weight is noticeable

Class 3: flattened lie of piles is not recovered and the impressedpattern of the weight can be confirmed

Class 4: flattened lie of piles is slightly recovered and the impressedpattern of the weight can be slightly confirmed

Class 5: flattened lie of piles is recovered and the impressed patternof the weight can not be noticed

(5) Scratch Resistance of Electrostatically Flocked Goods

The electrostatically flocked goods prepared by applying the flock tothe surface of a vinyl chloride sheet in a weight of 80-100 g/m² wereslowly scratched under a load of 1 kgf by using a copper coin having adiameter of 23.5 mm and a thickness of 1.5 mm and scar was judged by thefollowing three-grade criteria. The flocked goods were irradiated with afadeometer whose black panel temperature was set to 83° C. for 200hours, and then scratched by using the same copper coin and scar wasvisually judged.

Class 1: noticeable scar

Class 2: slight scar

Class 3: no scar

(6) Evaluation of Softness of Hand of Standing Fiber Surface in FlockedGoods

The hand of the standing fiber surface of the electrostatically flockedgoods prepared by applying the flock to the surface of a vinyl chloridesheet in a weight of 80-100 g/m² was organoleptically judged by fivepanelist according to the following three-grade criteria.

Excellent: very soft

Ordinary: slightly soft

Poor: hard

(7) Measurement of Maximum Extension and Elastic Modulus of Fiber

The properties were measured according to JIS L-1013, L-1015 and L-1095,respectively.

EXAMPLE 1

Poly(trimethylene terephthalate) having ηsp/c of 0.8 was spun under theconditions of a spinning temperature of 275° C. and a spinning rate of1200 m/min to obtain an unstretched yarn, which was then stretched underthe conditions of a hot roll temperature of 55° C., a hot platetemperature of 140° C., a stretching ratio of three times and astretching rate of 800 m/min to obtain a stretched yarn (having circularsection) having 100d/48f. The maximum extension, elastic modulus andelastic recovery at 20% extension of the stretched yarn were 4.0 g/d,30%, 26 g/d and 90%, respectively.

ηsp/c was determined as follows. That is, a polymer was dissolved at 90°C. in o-chlorophenol in a concentration of 1 g/dl and the resultingsolution was transferred to an Ostwald viscometer. Then, the viscositywas measured at 35° C. and asp/c was calculated by the followingequation:

ηsp/c=(T/T₀−1)/C

where T denotes a dropping time (seconds) of a sample solution, T₀denotes a dropping time (seconds) of a solvent, and C denotes aconcentration of a solution (g/dl).

The resulting poly(trimethylene terephthalate) fibers were bundled toform a tow having 1,000,000 denier, which was cut into pieces having alength of 1.0 mm by using a guillotine cutter. The resulting shortfibers were dipped in an aqueous solution comprising 1.5% sodiumsilicate and 3% colloidal silica (adjusted to pH 4 using acetic acid) at40° C. for 14 minutes, dehydrated, and subsequently dried to obtainpre-electrostatic flocking-treated fibers. The resulting short fibersexhibited a mesh pass percentage of 75% and had an excellentdispersibility. Then, an electrostatically flocked goods were preparedby applying 10 g of the electrostatically flocked short fibers as pilesto a 10×10 cm fabric substrate obtained by uniformly coating the surfaceof a vinyl chloride sheet with an acrylic resin as an adhesive under theconditions of a voltage of 25 KV and a distance between electrodes of 10cm.

The resulting electrostatically flocked good exhibited an excellentappearance (class 5) and an excellent softness. The electrostaticallyflocked goods exhibited a tread-proofness (class 5) and a scratchresistance (class 3) that was superior in recovery of piles. Theelectrostatically flocked good exhibited a scratch resistance afterfadeometer exposure (class 3) that was superior in light resistance.

COMPARATIVE EXAMPLE 1

In the same manner as in Example 1, except that a nylon 6 fiber (singleyarn denier: 2d, circular cross section) was used in place of thepoly(trimethylene terephthalate) fiber, an electrostatically flockedgoods were prepared. The resulting short fiber exhibited a mesh passpercentage of 63% so that it was inferior in dispersibility to Example1.

The resulting electrostatically flocked goods exhibited appearance(class 4) and ordinary softness so that it was inferior to Example 1.The electrostatically flocked goods exhibited a tread-proofness(class 1) that was markedly inferior to Example 1. Furthermore, theelectrostatically flocked good exhibited scratch resistance (class 3)that was the same as in Example 1, however, the scratch resistance afterfadeometer exposure was lowered to class 1 so that it was inferior inlight resistance.

COMPARATIVE EXAMPLE 2

In the same manner as in Example 1, except that a poly(ethyleneterephthalate) fiber (single yarn denier: 2d, circular cross-section)was used in place of the poly(trimethylene terephthalate) fiber, anelectrostatically flocked goods were prepared. The resulting short fiberexhibited a mesh pass percentage of 66% so that it was inferior indispersibility to Example 1.

The resulting electrostatically flocked good exhibited appearance(class 1) and poor softness so that it was markedly inferior toExample 1. The electrostatically flocked good exhibited class 1 in allitems of the tread-proofness, scratch resistance and scratch resistanceafter fadeomater exposure so that it was markedly inferior to Example 1.

EXAMPLES 2 to 8

In the same manner as in Example 1, except that the condition of thespinning temperature and spinning rate were changed, an unstretched yarnwas made and then draw-twisted to prepare fibers having a differentelastic recovery (65-95%) from that of Example 1 as shown in Table 1.

In the same manner as in Example 1, except that differentpoly(trimethylene terephthalate) fibers were used, electrostaticallyflocked goods were prepared. The mesh pass percentages of the resultingshort fibers was 75% or more so that the resulting electrostaticallyflocked goods were superior in dispersibility, like Example 1.

The appearance, softness, tread-proofness and scratch resistance of theresulting electrostatically flocked goods were as shown in Table 1.Comparing the electrostatically flocked goods having an elastic modulusof 85% or less with the electrostatically flocked goods having anelastic modulus of 87% or more, the latter were superior in appearance,tread-proofness and scratch resistance.

EXAMPLE 9

In the same manner as in Example 1, a poly(trimethylene terephthalate)stretched yarn (circular cross-section) having 75d/72f was obtained. Themaximum extension, elastic modulus and elastic recovery at 20% extensionof the stretched yarn were 4.2 g/d, 37%, 26 g/d and 89%, respectively.In the same manner as in Example 1, an electrostatically flocked goodswere prepared. The mesh pass percentage of the resulting short fiber was70%.

The resulting electrostatically flocked goods exhibited an excellentappearance (class 5) and an excellent softness. The electrostaticallyflocked goods exhibited a tread-proofness (class 4) and scratchresistance (class 3) so that it was superior in recovery of piles, andexhibited a scratch resistance after fadeometer exposure (class 3) sothat it was also superior in light resistance.

COMPARATIVE EXAMPLE 3

In the same manner as in Example 9, except that a nylon 6 fiber (singleyarn denier: 1d, circular cross-section) was used in place of thepoly(trimethylene terephthalate) fiber, electrostatically flocked goodswere prepared. The resulting short fiber exhibited a mesh passpercentage of 62% so that it was inferior in dispersibility to Example9.

The resulting electrostatically flocked goods exhibited an appearance(class 4) and ordinary softness so that they were inferior to Example 9.The electrostatically flocked goods exhibited tread-proofness (class 1)so that they were drastically inferior to Example 9. Furthermore, theelectrostatically flocked goods exhibited scratch resistance (class 2)that was inferior to Example 9, and the scratch resistance afterfadeometer exposure was lowered to class 1 so that it was inferior inlight resistance.

COMPARATIVE EXAMPLE 4

In the same manner as in Example 9, except that a poly(ethyleneterephthalate) fiber (single yarn denier: 1d, circular section) was usedin place of the poly(trimethylene terephthalate) fiber,electrostatically flocked goods were prepared. The resulting short fiberexhibited a mesh pass percentage of 45% so that it was inferior indispersibility to Example 9.

The resulting electrostatically flocked goods exhibited an appearance(class 1) and a poor softness so that it was drastically inferior toExample 9. Furthermore, the electrostatically flocked goods exhibitedclass 1 in all items of tread-proofness, scratch resistance and scratchresistance after fadeomater exposure so that it was drastically inferiorto Example 9.

TABLE 1 Examples 1 2 3 4 5 6 Fibers PTT PTT PTT PTT PTT PTT Single yarndenier (d) 2.1 2.1 2.1 2.1 2.1 2.1 Cut length (mm) 1.0 1.0 1.0 1.0 1.01.0 Elastic recovery (%) 90 65 70 80 83 85 Mesh pass (%) 75 75 77 80 7475 Appearance (class) 5 4 4 4 4 5 Softness Excellent Excellent ExcellentExcellent Excellent Excellent Tread-proofness (class) 5 3 4 4 4 4Scratch Initial 3 2 2 2 2 2 resistance After light 3 2 2 2 2 2 (class)exposure Examples Comparative Examples 7 8 9 1 2 3 4 Fibers PTT*1 PTTPTT N6 PET N6 PET Single yarn denier (d) 2.1 2.1 1.0 2.0 2.0 1.0 1.0 Cutlength (mm) 1.0 1.0 0.6 1.0 1.0 0.6 0.6 Elastic recovery (%) 87 95 89 6229 60 31 Mesh pass (%) 77 76 70 63 66 62 45 Appearance (class) 5 5 5 4 14 1 Softness Excellent Excellent Excellent Ordinary Poor Ordinary PoorTread-proofness (class) 5 5 4 1 1 1 1 Scratch Initial 3 3 3 3 1 2 1resistance After light 3 3 3 1 1 1 1 (class) exposure PTT:Poly(trimethylene terephthalate) fiber N6: Nylon 6 fiber PET:Poly(ethylene terephthalate) fiber

INDUSTRIAL APPLICABILITY

The fiber for electrostatic flocking of the present invention issuperior in dispersibility to a conventional fiber for electrostaticflocking, and the resultant electrostatically flocked goods are superiorin appearance, tread-proofness, scratch resistance and light resistanceto a conventional one. Accordingly, the electrostatically flocked goodsof the present invention are suited for use as automotive interiormaterials, for example, car seat coverings, pillars, dash boards,linings for doors and ceiling materials. When using the goods of thepresent invention as pillars and dash boards, it is directly flocked toa resin molded article, or flocked goods obtained by flocking to an anyfabric substrate are applied and assembled by using a tool such aswooden hammer. Therefore, the goods of the present invention are hardlyscratched on assembly. In addition, the electrostatically flocked goodsof the present invention are suited for use in furniture and chaircoverings, toys, ornaments and footwear.

What is claimed is:
 1. A fiber for electrostatic flocking, characterizedin that said fiber is a poly(trimethylene terephthalate) short fiberhaving a cut length of 0.2-3 mm.
 2. Electrostatically flocked goods,characterized in that said electrostatically flocked goods are preparedby electrostatically flocking said fiber for electrostatic flocking ofclaim 1.